People walk down a flooded road in Hampstead, N.C., on Saturday, August 9, 2014. Heavy rain is forecast in the Northeast on Tuesday and Wednesday. / Matt Born, AP

by Doyle Rice, USA TODAY

by Doyle Rice, USA TODAY

Drenching rain could lead to flash floods in much of the Mid-Atlantic and Northeast on Tuesday and into Wednesday.

The National Weather Service has placed parts of the region under a flash flood watch. This includes the entire New York City metro area and most of southern New England.

"Rainfall rates of 1 to 2 inches per hour are likely during the periods of heaviest rain," according to an online forecast from the weather service in New York. "Widespread rainfall amounts of 2 to 3 inches and locally over 4 inches are possible."

Rainfall of this intensity and magnitude could cause significant urban and poor drainage flooding, the weather service warned. Flooding of small streams is also possible.

"The evening commute on Tuesday will be very slow from New York City to Philadelphia," reports AccuWeather meteorologist Brian Edwards. "Some commuters may even face detours around any localized flooding problems that develop."

Delta Air Lines is waiving change fees for flights in the mid-Atlantic and New York City areas ahead of the storms.

Severe thunderstorms could also rattle portions of eastern Ohio, western Pennsylvania, West Virginia, Maryland, Virginia and Delaware on Tuesday, the Storm Prediction Center forecasts. The main threats will be damaging wind gusts and large hail.